Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Christopher Schultz]

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Tsirkin,

On 2/24/2010 2:21 AM, Tsirkin Evgeny wrote:
> On Tue, Feb 23, 2010 at 11:50 PM, Christopher Schultz <
> ch...@christopherschultz.net> wrote:
> 
>> -BEGIN PGP SIGNED MESSAGE->> What's "flow-resuming" is ?How a
>> request can be "resumed" ?Doesn't this goes
 againt the idea
 of "http is staitless" ,that's vrey interesting?
>>
>>
> So,the "flow-resuming" you were talking about is just the mechanism of
> storing the
> request parameters and url and use them again after successful
> authentication,right?

It also stores POST message bodies up to a certain size.

> Yes,this probably would not work with custom session ,since tomcat probably
> stores the parameters and url in session.

Tomcat definitely does, under the session "note", which is a
Tomcat-specific implementation detail.

> For this particular issue however i have implemented my own mechanism
> using custom cookies (server side cookies).

Server-side cookies? Sounds like a winner.

- -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Tsirkin Evgeny]

On Tue, Feb 23, 2010 at 11:50 PM, Christopher Schultz <
ch...@christopherschultz.net> wrote:

> -BEGIN PGP SIGNED MESSAGE->> What's "flow-resuming" is ?How a
> request can be "resumed" ?Doesn't this goes
> >> againt the idea
> >> of "http is staitless" ,that's vrey interesting?
>
>
So,the "flow-resuming" you were talking about is just the mechanism of
storing the
request parameters and url and use them again after successful
authentication,right?
Yes,this probably would not work with custom session ,since tomcat probably
stores the parameters and url in session.
For this particular issue however i have implemented my own mechanism
using custom cookies (server side cookies).
Of course,all this is probably can not be reused and is tied to my
particular
env. .
But it is a "yes this can be done if really needed" email.
Evgeny


> See section 12.5.3 of the servlet (2.5) specification which lays this
> all out in plain English.
>
> - -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Christopher Schultz]

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Tsirkin,

On 2/23/2010 1:49 PM, Tsirkin Evgeny wrote:
> On Tue, Feb 23, 2010 at 8:08 PM, Christopher Schultz <
> ch...@christopherschultz.net> wrote:
>> I guess tomcat authentication is broken for me - tomcat is probably writing
>> something in
>> session _ before _ the filter loads the data into it from db.

That is true: Tomcat does session work /before/ filters are invoked, but
it also has something called the "session note" which is essentially a
private attribute that can be used for things like authentication state
information. The HttpSession has no access to this except through
introspection, which could be disabled by a SecurityManager I'd imagine.

>> This probably can be fixed if i do not rip the "old" data written by tomcat
>> and just add my own ,but i just don't use tomcat auth.

If you're not using container-based authentication, then I guess it
doesn't matter.

> That means that things like flow-resuming (where your original
> request is re-submitted after successful authentication) won't work.
> 
> 
>> What's "flow-resuming" is ?How a request can be "resumed" ?Doesn't this goes
>> againt the idea
>> of "http is staitless" ,that's vrey interesting?

See section 12.5.3 of the servlet (2.5) specification which lays this
all out in plain English.

- -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Tsirkin Evgeny]

On Tue, Feb 23, 2010 at 8:08 PM, Christopher Schultz <
ch...@christopherschultz.net> wrote:

> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> Tsirkin,
>
> On 2/23/2010 1:51 AM, Tsirkin Evgeny wrote:
> > What we did - override session object using filter.On each request start
> it
> > would
> > read it's info from db (any configured one ,but preferring the local one)
> > On each request end it would write itself into ALL dbs that are
> configured
> > to be
> > used.
>
> This could have been done using standard Tomcat components and a shared
> session-only database.


Which means running another mysql instance just for it,
And on what machine - there are 2 equivalent machines ,no separate db one.


> Or, a pair of MysQL databases rigged to hot-copy
> each other.
>
>
Unfortunately i think that mysql just don't know how to do master-master
cluster (maybe in newer
versions it does).


> I think you did more work than necessary. Does this work with
> authentication?



> Tomcat adds information to the session that isn't part
> of the attributes, so a standard HttpSession wrapper won't be able to
> replicate this information between the nodes.


I guess tomcat authentication is broken for me - tomcat is probably writing
something in
session _ before _ the filter loads the data into it from db.
This probably can be fixed if i do not rip the "old" data written by tomcat
and just
add my own ,but i just don't use tomcat auth.


> That means that things
> like flow-resuming (where your original request is re-submitted after
> successful authentication) won't work.
>
>

What's "flow-resuming" is ?How a request can be "resumed" ?Doesn't this goes
againt the idea
of "http is staitless" ,that's vrey interesting?
Evgeny


> - -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Christopher Schultz]

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Tsirkin,

On 2/23/2010 1:51 AM, Tsirkin Evgeny wrote:
> What we did - override session object using filter.On each request start it
> would
> read it's info from db (any configured one ,but preferring the local one)
> On each request end it would write itself into ALL dbs that are configured
> to be
> used.

This could have been done using standard Tomcat components and a shared
session-only database. Or, a pair of MysQL databases rigged to hot-copy
each other.

I think you did more work than necessary. Does this work with
authentication? Tomcat adds information to the session that isn't part
of the attributes, so a standard HttpSession wrapper won't be able to
replicate this information between the nodes. That means that things
like flow-resuming (where your original request is re-submitted after
successful authentication) won't work.

- -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Jon Brisbin]

On Feb 23, 2010, at 7:31 AM, Simone Tripodi wrote:

> Hi Evgeny,
> thanks a lot for shared your experience, very interesting. I'd like to
> plug something magic that could avoid me configuring a filter, I
> started investigating about a possible use of AOP & HttpSession.
> If anyone is interested, I'll share my results when done.

This sound very interesting to me. I'd love to take a look at it when you're 
done. I'm still fighting load-balancing issues.

Jon Brisbin
Portal Webmaster
NPC International, Inc.


> Best regards!!!
> Simo
> 
> http://people.apache.org/~simonetripodi/
> 
> 
> 
> On Tue, Feb 23, 2010 at 7:51 AM, Tsirkin Evgeny  wrote:
>> Just in case somebody will google for a solution for "replacing session".
>> I have done this .
>> First of all ,why:
>> We have cluster of 2 machines .
>> Each have a separate db on it .
>> The machines are sharing information using nfs mounting fs.
>> Each machine runs it's own apache server ,(no apache balancer in front).
>> There IS a hardware load balancer in front of this but sometime it fails
>> to route already open sessions to same host.
>> So,we can't :
>> 1. share sessions using files ,because this would be same file for 2 tomcats
>>and because this would fail on nfs .
>> 2. we can't use tomcat cluster because there are cases when BOTH tomcat
>>would be shut down or restarted and session would be loosed.
>> 3. we can't use a db because there is no central db - each host has it's own
>> one.
>> 4. to complicate issue machines could be added/removed to the cluster.
>> 
>> What we did - override session object using filter.On each request start it
>> would
>> read it's info from db (any configured one ,but preferring the local one)
>> On each request end it would write itself into ALL dbs that are configured
>> to be
>> used.
>> Although the obvious problem here is the writing to more then 1 db and
>> reading
>> from a db on each request ,this really works good thanks for mysql to be
>> so fast on simple read/write.
>> I have even implemented a simple lock mechanism for session .
>> What more - this solution is portable ,it worked for us on SunONE server
>> and now on tomcat.
>> Thanks
>> Evgeny
>> On Tue, Feb 16, 2010 at 9:54 PM, Simone Tripodi 
>> wrote:
>> 
>>> Hi Martin,
>>> very interesting, thanks for share it!!! I did, more or less, the same
>>> on a project for a customer, but it was strictly related to the
>>> application, your stuff looks much much better of mine and it is a
>>> reusable module.
>>> All the best,
>>> Simo
>>> 
>>> http://people.apache.org/~simonetripodi/
>>> 
>>> 
>>> 
>>> On Tue, Feb 16, 2010 at 6:02 PM, Martin Grotzke
>>>  wrote:
 Hi Jon,
 
 On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
> I'm trying to figure out today how I can implement a Valve or something
>>> that can store a session to a backend DB and reload that session on another
>>> Tomcat instance similar to how the PersistentManager loads user's session
>>> after a restart.
> 
> Would a Valve based on PersistentValve allow me to implement a
>>> cluster-like solution such that a user login causes a write to a central
>>> database and a load balanced request to another server would see that user
>>> without forcing another login?
 You might have a look at the
 http://code.google.com/p/memcached-session-manager/ which is a session
 failover solution storing sessions in memcached.
 
 When the project was created I only thought of applications using sticky
 sessions but it should also work with non-sticky sessions if sessions
 are stored in memcached synchronously (sessionBackupAsync needs to be
 set to false, see [1]).
 
 The memcached-session-manager basically is a session manager
 implemention, the most interesting part is the
 MemcachedBackupSessionManager ([2]) if you want to have a look at the
 code.
 
 Cheers,
 Martin
 
 
 [1]
>>> http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
 [2]
>>> http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java
 
 
 
> 
> Jon Brisbin
> Portal Webmaster
> NPC International, Inc.
> 
> 
> 
> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
> 
>> Hi all guys and very nice to meet the Tomcat community,
>> I've a web-application that needs to be replicated in more than one
>> Tomcat, and since it is HttpSession based, I need to enable the
>> session replication.
>> Even if I work with very good sysadmins that know how to do it, I'm
>> curious and would like to know if I could replace the HttpSession
>> implementation with a my own one, I'd like to integrate Hazelcast[1]
>> for data synchronization.
>> Thanks in advance, every suggestion will be very appreciated.
>> Simo
>> 

Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Simone Tripodi]

Hi Evgeny,
thanks a lot for shared your experience, very interesting. I'd like to
plug something magic that could avoid me configuring a filter, I
started investigating about a possible use of AOP & HttpSession.
If anyone is interested, I'll share my results when done.
Best regards!!!
Simo

http://people.apache.org/~simonetripodi/



On Tue, Feb 23, 2010 at 7:51 AM, Tsirkin Evgeny  wrote:
> Just in case somebody will google for a solution for "replacing session".
> I have done this .
> First of all ,why:
> We have cluster of 2 machines .
> Each have a separate db on it .
> The machines are sharing information using nfs mounting fs.
> Each machine runs it's own apache server ,(no apache balancer in front).
> There IS a hardware load balancer in front of this but sometime it fails
> to route already open sessions to same host.
> So,we can't :
> 1. share sessions using files ,because this would be same file for 2 tomcats
>    and because this would fail on nfs .
> 2. we can't use tomcat cluster because there are cases when BOTH tomcat
>    would be shut down or restarted and session would be loosed.
> 3. we can't use a db because there is no central db - each host has it's own
> one.
> 4. to complicate issue machines could be added/removed to the cluster.
>
> What we did - override session object using filter.On each request start it
> would
> read it's info from db (any configured one ,but preferring the local one)
> On each request end it would write itself into ALL dbs that are configured
> to be
> used.
> Although the obvious problem here is the writing to more then 1 db and
> reading
> from a db on each request ,this really works good thanks for mysql to be
> so fast on simple read/write.
> I have even implemented a simple lock mechanism for session .
> What more - this solution is portable ,it worked for us on SunONE server
> and now on tomcat.
> Thanks
> Evgeny
> On Tue, Feb 16, 2010 at 9:54 PM, Simone Tripodi 
> wrote:
>
>> Hi Martin,
>> very interesting, thanks for share it!!! I did, more or less, the same
>> on a project for a customer, but it was strictly related to the
>> application, your stuff looks much much better of mine and it is a
>> reusable module.
>> All the best,
>> Simo
>>
>> http://people.apache.org/~simonetripodi/
>>
>>
>>
>> On Tue, Feb 16, 2010 at 6:02 PM, Martin Grotzke
>>  wrote:
>> > Hi Jon,
>> >
>> > On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
>> >> I'm trying to figure out today how I can implement a Valve or something
>> that can store a session to a backend DB and reload that session on another
>> Tomcat instance similar to how the PersistentManager loads user's session
>> after a restart.
>> >>
>> >> Would a Valve based on PersistentValve allow me to implement a
>> cluster-like solution such that a user login causes a write to a central
>> database and a load balanced request to another server would see that user
>> without forcing another login?
>> > You might have a look at the
>> > http://code.google.com/p/memcached-session-manager/ which is a session
>> > failover solution storing sessions in memcached.
>> >
>> > When the project was created I only thought of applications using sticky
>> > sessions but it should also work with non-sticky sessions if sessions
>> > are stored in memcached synchronously (sessionBackupAsync needs to be
>> > set to false, see [1]).
>> >
>> > The memcached-session-manager basically is a session manager
>> > implemention, the most interesting part is the
>> > MemcachedBackupSessionManager ([2]) if you want to have a look at the
>> > code.
>> >
>> > Cheers,
>> > Martin
>> >
>> >
>> > [1]
>> http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
>> > [2]
>> http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java
>> >
>> >
>> >
>> >>
>> >> Jon Brisbin
>> >> Portal Webmaster
>> >> NPC International, Inc.
>> >>
>> >>
>> >>
>> >> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
>> >>
>> >> > Hi all guys and very nice to meet the Tomcat community,
>> >> > I've a web-application that needs to be replicated in more than one
>> >> > Tomcat, and since it is HttpSession based, I need to enable the
>> >> > session replication.
>> >> > Even if I work with very good sysadmins that know how to do it, I'm
>> >> > curious and would like to know if I could replace the HttpSession
>> >> > implementation with a my own one, I'd like to integrate Hazelcast[1]
>> >> > for data synchronization.
>> >> > Thanks in advance, every suggestion will be very appreciated.
>> >> > Simo
>> >> >
>> >> > [1] http://www.hazelcast.com/
>> >> >
>> >> > http://people.apache.org/~simonetripodi/
>> >> >
>> >> > -
>> >> > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
>> >> > For additional commands, e-mai

Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Tsirkin Evgeny]

Just in case somebody will google for a solution for "replacing session".
I have done this .
First of all ,why:
We have cluster of 2 machines .
Each have a separate db on it .
The machines are sharing information using nfs mounting fs.
Each machine runs it's own apache server ,(no apache balancer in front).
There IS a hardware load balancer in front of this but sometime it fails
to route already open sessions to same host.
So,we can't :
1. share sessions using files ,because this would be same file for 2 tomcats
and because this would fail on nfs .
2. we can't use tomcat cluster because there are cases when BOTH tomcat
would be shut down or restarted and session would be loosed.
3. we can't use a db because there is no central db - each host has it's own
one.
4. to complicate issue machines could be added/removed to the cluster.

What we did - override session object using filter.On each request start it
would
read it's info from db (any configured one ,but preferring the local one)
On each request end it would write itself into ALL dbs that are configured
to be
used.
Although the obvious problem here is the writing to more then 1 db and
reading
from a db on each request ,this really works good thanks for mysql to be
so fast on simple read/write.
I have even implemented a simple lock mechanism for session .
What more - this solution is portable ,it worked for us on SunONE server
and now on tomcat.
Thanks
Evgeny
On Tue, Feb 16, 2010 at 9:54 PM, Simone Tripodi wrote:

> Hi Martin,
> very interesting, thanks for share it!!! I did, more or less, the same
> on a project for a customer, but it was strictly related to the
> application, your stuff looks much much better of mine and it is a
> reusable module.
> All the best,
> Simo
>
> http://people.apache.org/~simonetripodi/
>
>
>
> On Tue, Feb 16, 2010 at 6:02 PM, Martin Grotzke
>  wrote:
> > Hi Jon,
> >
> > On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
> >> I'm trying to figure out today how I can implement a Valve or something
> that can store a session to a backend DB and reload that session on another
> Tomcat instance similar to how the PersistentManager loads user's session
> after a restart.
> >>
> >> Would a Valve based on PersistentValve allow me to implement a
> cluster-like solution such that a user login causes a write to a central
> database and a load balanced request to another server would see that user
> without forcing another login?
> > You might have a look at the
> > http://code.google.com/p/memcached-session-manager/ which is a session
> > failover solution storing sessions in memcached.
> >
> > When the project was created I only thought of applications using sticky
> > sessions but it should also work with non-sticky sessions if sessions
> > are stored in memcached synchronously (sessionBackupAsync needs to be
> > set to false, see [1]).
> >
> > The memcached-session-manager basically is a session manager
> > implemention, the most interesting part is the
> > MemcachedBackupSessionManager ([2]) if you want to have a look at the
> > code.
> >
> > Cheers,
> > Martin
> >
> >
> > [1]
> http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
> > [2]
> http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java
> >
> >
> >
> >>
> >> Jon Brisbin
> >> Portal Webmaster
> >> NPC International, Inc.
> >>
> >>
> >>
> >> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
> >>
> >> > Hi all guys and very nice to meet the Tomcat community,
> >> > I've a web-application that needs to be replicated in more than one
> >> > Tomcat, and since it is HttpSession based, I need to enable the
> >> > session replication.
> >> > Even if I work with very good sysadmins that know how to do it, I'm
> >> > curious and would like to know if I could replace the HttpSession
> >> > implementation with a my own one, I'd like to integrate Hazelcast[1]
> >> > for data synchronization.
> >> > Thanks in advance, every suggestion will be very appreciated.
> >> > Simo
> >> >
> >> > [1] http://www.hazelcast.com/
> >> >
> >> > http://people.apache.org/~simonetripodi/
> >> >
> >> > -
> >> > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> >> > For additional commands, e-mail: users-h...@tomcat.apache.org
> >> >
> >>
> >>
> >> -
> >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> >> For additional commands, e-mail: users-h...@tomcat.apache.org
> >>
> >
> > --
> >
>
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>
>

Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Simone Tripodi]

Hi Martin,
very interesting, thanks for share it!!! I did, more or less, the same
on a project for a customer, but it was strictly related to the
application, your stuff looks much much better of mine and it is a
reusable module.
All the best,
Simo

http://people.apache.org/~simonetripodi/



On Tue, Feb 16, 2010 at 6:02 PM, Martin Grotzke
 wrote:
> Hi Jon,
>
> On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
>> I'm trying to figure out today how I can implement a Valve or something that 
>> can store a session to a backend DB and reload that session on another 
>> Tomcat instance similar to how the PersistentManager loads user's session 
>> after a restart.
>>
>> Would a Valve based on PersistentValve allow me to implement a cluster-like 
>> solution such that a user login causes a write to a central database and a 
>> load balanced request to another server would see that user without forcing 
>> another login?
> You might have a look at the
> http://code.google.com/p/memcached-session-manager/ which is a session
> failover solution storing sessions in memcached.
>
> When the project was created I only thought of applications using sticky
> sessions but it should also work with non-sticky sessions if sessions
> are stored in memcached synchronously (sessionBackupAsync needs to be
> set to false, see [1]).
>
> The memcached-session-manager basically is a session manager
> implemention, the most interesting part is the
> MemcachedBackupSessionManager ([2]) if you want to have a look at the
> code.
>
> Cheers,
> Martin
>
>
> [1] 
> http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
> [2] 
> http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java
>
>
>
>>
>> Jon Brisbin
>> Portal Webmaster
>> NPC International, Inc.
>>
>>
>>
>> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
>>
>> > Hi all guys and very nice to meet the Tomcat community,
>> > I've a web-application that needs to be replicated in more than one
>> > Tomcat, and since it is HttpSession based, I need to enable the
>> > session replication.
>> > Even if I work with very good sysadmins that know how to do it, I'm
>> > curious and would like to know if I could replace the HttpSession
>> > implementation with a my own one, I'd like to integrate Hazelcast[1]
>> > for data synchronization.
>> > Thanks in advance, every suggestion will be very appreciated.
>> > Simo
>> >
>> > [1] http://www.hazelcast.com/
>> >
>> > http://people.apache.org/~simonetripodi/
>> >
>> > -
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Martin Grotzke]

Hi Jon,

On Mon, 2010-02-15 at 11:55 -0600, Jon Brisbin wrote:
> I'm trying to figure out today how I can implement a Valve or something that 
> can store a session to a backend DB and reload that session on another Tomcat 
> instance similar to how the PersistentManager loads user's session after a 
> restart.
> 
> Would a Valve based on PersistentValve allow me to implement a cluster-like 
> solution such that a user login causes a write to a central database and a 
> load balanced request to another server would see that user without forcing 
> another login?
You might have a look at the
http://code.google.com/p/memcached-session-manager/ which is a session
failover solution storing sessions in memcached.

When the project was created I only thought of applications using sticky
sessions but it should also work with non-sticky sessions if sessions
are stored in memcached synchronously (sessionBackupAsync needs to be
set to false, see [1]).

The memcached-session-manager basically is a session manager
implemention, the most interesting part is the
MemcachedBackupSessionManager ([2]) if you want to have a look at the
code.

Cheers,
Martin


[1] 
http://code.google.com/p/memcached-session-manager/wiki/SetupAndConfiguration
[2] 
http://github.com/magro/memcached-session-manager/blob/master/core/src/main/java/de/javakaffee/web/msm/MemcachedBackupSessionManager.java



> 
> Jon Brisbin
> Portal Webmaster
> NPC International, Inc.
> 
> 
> 
> On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:
> 
> > Hi all guys and very nice to meet the Tomcat community,
> > I've a web-application that needs to be replicated in more than one
> > Tomcat, and since it is HttpSession based, I need to enable the
> > session replication.
> > Even if I work with very good sysadmins that know how to do it, I'm
> > curious and would like to know if I could replace the HttpSession
> > implementation with a my own one, I'd like to integrate Hazelcast[1]
> > for data synchronization.
> > Thanks in advance, every suggestion will be very appreciated.
> > Simo
> > 
> > [1] http://www.hazelcast.com/
> > 
> > http://people.apache.org/~simonetripodi/
> > 
> > -
> > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> > For additional commands, e-mail: users-h...@tomcat.apache.org
> > 
> 
> 
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Simone Tripodi]

Hi Cris,
thanks for your reply and nice to meet you :)
There's no specific reason why I don't want to use the built-in
session replication, even if I'd be able to realize what I've in my
mind, the sysadmins will never let me know to use it since they're
confident with the Tomcat solution.
BTW, I'm just curious and like very much integrating heterogeneous
software layers in an original way, so before spending time in
studying the Tomcat code and understand how to realize my crazy stuff
I wrote the email :P
Thanks, all the best,
Simo

http://people.apache.org/~simonetripodi/



On Mon, Feb 15, 2010 at 6:10 PM, Christopher Schultz
 wrote:
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> Simone,
>
> On 2/15/2010 12:05 PM, Simone Tripodi wrote:
>> I've a web-application that needs to be replicated in more than one
>> Tomcat, and since it is HttpSession based, I need to enable the
>> session replication.
>> Even if I work with very good sysadmins that know how to do it, I'm
>> curious and would like to know if I could replace the HttpSession
>> implementation with a my own one, I'd like to integrate Hazelcast[1]
>> for data synchronization.
>
> Why not use the session replication that comes with Tomcat?
>
> Otherwise, presumably Hazelcast knows how to integrate their own product
> with Tomcat. You might have better luck asking them.
>
> - -chris
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> tPgAni7x4ZGDvBiT2+wIoPZ5QwuOBKNG
> =P+WC
> -END PGP SIGNATURE-
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>
>

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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Christopher Schultz]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Jon,

On 2/15/2010 12:55 PM, Jon Brisbin wrote:
> I'm using the built-in Tribes-based replication which works fine for
> short periods of time and under moderate to light load. Once the
> Tomcat server has been running for a day or two, though, this
> distributed session replication starts breaking unexpectedly. Once
> this happens, the apps start becoming unavailable until I restart
> everything.

That's unfortunate. You should post a complaint that you are observing
this behavior. AFAIK, the Tomcat devs are quite satisfied with their
replication implementation. Get ready to defend your use of session
objects, though :)

> I'm trying to figure out today how I can implement a Valve or
> something that can store a session to a backend DB and reload that
> session on another Tomcat instance similar to how the
> PersistentManager loads user's session after a restart.
> 
> Would a Valve based on PersistentValve allow me to implement a
> cluster-like solution such that a user login causes a write to a
> central database and a load balanced request to another server would
> see that user without forcing another login?

I would think that simply using the existing PersistenceManager +
JDBCStore would work. In tact, it's even documented to be one of the
ways of achieving session clustering without doing in-memory
replication: http://tomcat.apache.org/tomcat-6.0-doc/cluster-howto.html

Unfortunately, I didn't see any specifics on how to configure Tomcat to
do just that, though I must admit I didn't spend very much time looking.

- -chris
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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Jon Brisbin]

I'm just getting ready to ask a question like this, as I have a similar need.

I'm using the built-in Tribes-based replication which works fine for short 
periods of time and under moderate to light load. Once the Tomcat server has 
been running for a day or two, though, this distributed session replication 
starts breaking unexpectedly. Once this happens, the apps start becoming 
unavailable until I restart everything.

I'm trying to figure out today how I can implement a Valve or something that 
can store a session to a backend DB and reload that session on another Tomcat 
instance similar to how the PersistentManager loads user's session after a 
restart.

Would a Valve based on PersistentValve allow me to implement a cluster-like 
solution such that a user login causes a write to a central database and a load 
balanced request to another server would see that user without forcing another 
login?

Jon Brisbin
Portal Webmaster
NPC International, Inc.



On Feb 15, 2010, at 11:05 AM, Simone Tripodi wrote:

> Hi all guys and very nice to meet the Tomcat community,
> I've a web-application that needs to be replicated in more than one
> Tomcat, and since it is HttpSession based, I need to enable the
> session replication.
> Even if I work with very good sysadmins that know how to do it, I'm
> curious and would like to know if I could replace the HttpSession
> implementation with a my own one, I'd like to integrate Hazelcast[1]
> for data synchronization.
> Thanks in advance, every suggestion will be very appreciated.
> Simo
> 
> [1] http://www.hazelcast.com/
> 
> http://people.apache.org/~simonetripodi/
> 
> -
> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> For additional commands, e-mail: users-h...@tomcat.apache.org
> 


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Re: Is it possible to replace the HttpSession implementation in Tomcat?

[Christopher Schultz]

-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1

Simone,

On 2/15/2010 12:05 PM, Simone Tripodi wrote:
> I've a web-application that needs to be replicated in more than one
> Tomcat, and since it is HttpSession based, I need to enable the
> session replication.
> Even if I work with very good sysadmins that know how to do it, I'm
> curious and would like to know if I could replace the HttpSession
> implementation with a my own one, I'd like to integrate Hazelcast[1]
> for data synchronization.

Why not use the session replication that comes with Tomcat?

Otherwise, presumably Hazelcast knows how to integrate their own product
with Tomcat. You might have better luck asking them.

- -chris
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Is it possible to replace the HttpSession implementation in Tomcat?

[Simone Tripodi]

Hi all guys and very nice to meet the Tomcat community,
I've a web-application that needs to be replicated in more than one
Tomcat, and since it is HttpSession based, I need to enable the
session replication.
Even if I work with very good sysadmins that know how to do it, I'm
curious and would like to know if I could replace the HttpSession
implementation with a my own one, I'd like to integrate Hazelcast[1]
for data synchronization.
Thanks in advance, every suggestion will be very appreciated.
Simo

[1] http://www.hazelcast.com/

http://people.apache.org/~simonetripodi/

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